[Qemu-devel] [PATCH v2 0/6] nbd export qmp interface

[Qemu-devel] [PATCH v2 0/6] nbd export qmp interface

[Vladimir Sementsov-Ogievskiy]

v2:
01: tweak comment
    add Eric's r-b
02: new patch
03: rewritten, to move form 'bool force' flag to 'enum mode' parameter
04: add Eric's r-b
05: improve commit message
    tweak comment
06: rebase on 03 changes
    make PEP8 happy
    some other tweaks
    I've left nbd_port variable hard-set to 10900. I think all such things
    should be fixed together, and it is simple to change in future
    nbd_port = '10900'
    to
    nbd_port = iotests.get_free_port()
    if needed.

[Unfortunately, qmp query-nbd-server is not finished yet, coming soon,
 but may be after my vocation on the next week]

Vladimir Sementsov-Ogievskiy (6):
  qapi: add name parameter to nbd-server-add
  hmp: add name parameter to nbd_server_add
  qapi: add nbd-server-remove
  iotest 147: add cases to test new @name parameter of nbd-server-add
  iotests: implement QemuIoInteractive class
  iotest 201: new test for qmp nbd-server-remove

 qapi/block.json               |  54 +++++++++++++-
 include/block/nbd.h           |   1 +
 blockdev-nbd.c                |  38 ++++++++--
 hmp.c                         |   6 +-
 nbd/server.c                  |  21 ++++++
 hmp-commands.hx               |   9 +--
 tests/qemu-iotests/147        |  68 ++++++++++++++----
 tests/qemu-iotests/147.out    |   4 +-
 tests/qemu-iotests/201        | 159 ++++++++++++++++++++++++++++++++++++++++++
 tests/qemu-iotests/201.out    |   5 ++
 tests/qemu-iotests/group      |   1 +
 tests/qemu-iotests/iotests.py |  38 ++++++++++
 12 files changed, 376 insertions(+), 28 deletions(-)
 create mode 100644 tests/qemu-iotests/201
 create mode 100644 tests/qemu-iotests/201.out

-- 
2.11.1

[Qemu-devel] [PATCH v2 1/6] qapi: add name parameter to nbd-server-add

[Vladimir Sementsov-Ogievskiy]

Allow user to specify name for new export, to not reuse internal
node name and to not show it to clients.

This also allows creating several exports per device.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
---
 qapi/block.json |  9 +++++++--
 blockdev-nbd.c  | 14 +++++++++-----
 hmp.c           |  5 +++--
 3 files changed, 19 insertions(+), 9 deletions(-)

diff --git a/qapi/block.json b/qapi/block.json
index f093fa3f27..353e3a45bd 100644
--- a/qapi/block.json
+++ b/qapi/block.json
@@ -213,14 +213,19 @@
 #
 # @device: The device name or node name of the node to be exported
 #
+# @name: Export name. If unspecified, the @device parameter is used as the
+#        export name. (Since 2.12)
+#
 # @writable: Whether clients should be able to write to the device via the
 #     NBD connection (default false).
 #
-# Returns: error if the device is already marked for export.
+# Returns: error if the server is not running, or export with the same name
+#          already exists.
 #
 # Since: 1.3.0
 ##
-{ 'command': 'nbd-server-add', 'data': {'device': 'str', '*writable': 'bool'} }
+{ 'command': 'nbd-server-add',
+  'data': {'device': 'str', '*name': 'str', '*writable': 'bool'} }
 
 ##
 # @nbd-server-stop:
diff --git a/blockdev-nbd.c b/blockdev-nbd.c
index 9e3c22109c..104789e521 100644
--- a/blockdev-nbd.c
+++ b/blockdev-nbd.c
@@ -140,8 +140,8 @@ void qmp_nbd_server_start(SocketAddressLegacy *addr,
     qapi_free_SocketAddress(addr_flat);
 }
 
-void qmp_nbd_server_add(const char *device, bool has_writable, bool writable,
-                        Error **errp)
+void qmp_nbd_server_add(const char *device, bool has_name, const char *name,
+                        bool has_writable, bool writable, Error **errp)
 {
     BlockDriverState *bs = NULL;
     BlockBackend *on_eject_blk;
@@ -152,8 +152,12 @@ void qmp_nbd_server_add(const char *device, bool has_writable, bool writable,
         return;
     }
 
-    if (nbd_export_find(device)) {
-        error_setg(errp, "NBD server already exporting device '%s'", device);
+    if (!has_name) {
+        name = device;
+    }
+
+    if (nbd_export_find(name)) {
+        error_setg(errp, "NBD server already has export named '%s'", name);
         return;
     }
 
@@ -177,7 +181,7 @@ void qmp_nbd_server_add(const char *device, bool has_writable, bool writable,
         return;
     }
 
-    nbd_export_set_name(exp, device);
+    nbd_export_set_name(exp, name);
 
     /* The list of named exports has a strong reference to this export now and
      * our only way of accessing it is through nbd_export_find(), so we can drop
diff --git a/hmp.c b/hmp.c
index c6bab5373b..37972f8322 100644
--- a/hmp.c
+++ b/hmp.c
@@ -2218,7 +2218,8 @@ void hmp_nbd_server_start(Monitor *mon, const QDict *qdict)
             continue;
         }
 
-        qmp_nbd_server_add(info->value->device, true, writable, &local_err);
+        qmp_nbd_server_add(info->value->device, false, NULL,
+                           true, writable, &local_err);
 
         if (local_err != NULL) {
             qmp_nbd_server_stop(NULL);
@@ -2238,7 +2239,7 @@ void hmp_nbd_server_add(Monitor *mon, const QDict *qdict)
     bool writable = qdict_get_try_bool(qdict, "writable", false);
     Error *local_err = NULL;
 
-    qmp_nbd_server_add(device, true, writable, &local_err);
+    qmp_nbd_server_add(device, false, NULL, true, writable, &local_err);
 
     if (local_err != NULL) {
         hmp_handle_error(mon, &local_err);
-- 
2.11.1

[Qemu-devel] [PATCH v2 2/6] hmp: add name parameter to nbd_server_add

[Vladimir Sementsov-Ogievskiy]

Support name parameter for HMP too.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
 hmp.c           | 3 ++-
 hmp-commands.hx | 9 +++++----
 2 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/hmp.c b/hmp.c
index 37972f8322..964cff8aed 100644
--- a/hmp.c
+++ b/hmp.c
@@ -2236,10 +2236,11 @@ exit:
 void hmp_nbd_server_add(Monitor *mon, const QDict *qdict)
 {
     const char *device = qdict_get_str(qdict, "device");
+    const char *name = qdict_get_try_str(qdict, "name");
     bool writable = qdict_get_try_bool(qdict, "writable", false);
     Error *local_err = NULL;
 
-    qmp_nbd_server_add(device, false, NULL, true, writable, &local_err);
+    qmp_nbd_server_add(device, name != NULL, name, true, writable, &local_err);
 
     if (local_err != NULL) {
         hmp_handle_error(mon, &local_err);
diff --git a/hmp-commands.hx b/hmp-commands.hx
index 6d5ebdf6ab..cad9a9a238 100644
--- a/hmp-commands.hx
+++ b/hmp-commands.hx
@@ -1553,8 +1553,8 @@ ETEXI
 
     {
         .name       = "nbd_server_add",
-        .args_type  = "writable:-w,device:B",
-        .params     = "nbd_server_add [-w] device",
+        .args_type  = "name:-n,writable:-w,device:B",
+        .params     = "nbd_server_add [-n] [-w] device",
         .help       = "export a block device via NBD",
         .cmd        = hmp_nbd_server_add,
     },
@@ -1562,8 +1562,9 @@ STEXI
 @item nbd_server_add @var{device}
 @findex nbd_server_add
 Export a block device through QEMU's NBD server, which must be started
-beforehand with @command{nbd_server_start}.  The @option{-w} option makes the
-exported device writable too.
+beforehand with @command{nbd_server_start}. The @option{-n} option sets export
+name. If @option{-n} option is unspecified, the @var{device} parameter is used.
+The @option{-w} option makes the exported device writable too.
 ETEXI
 
     {
-- 
2.11.1

[Qemu-devel] [PATCH v2 3/6] qapi: add nbd-server-remove

[Vladimir Sementsov-Ogievskiy]

Add command for export removing. It is needed for cases when we
don't want to keep export after the operation on it was completed.
The other example is temporary node, created with blockdev-add.
If we want to delete it we should firstly remove corresponding
NBD export.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
 qapi/block.json     | 45 +++++++++++++++++++++++++++++++++++++++++++++
 include/block/nbd.h |  1 +
 blockdev-nbd.c      | 24 ++++++++++++++++++++++++
 nbd/server.c        | 21 +++++++++++++++++++++
 4 files changed, 91 insertions(+)

diff --git a/qapi/block.json b/qapi/block.json
index 353e3a45bd..ddf73932ce 100644
--- a/qapi/block.json
+++ b/qapi/block.json
@@ -228,6 +228,51 @@
   'data': {'device': 'str', '*name': 'str', '*writable': 'bool'} }
 
 ##
+# @NbdServerRemoveMode:
+#
+# Mode of NBD export removing.
+#
+# @safe: Remove export if there are no existing connections, fail otherwise.
+#
+# @hard: Drop all connections immediately and remove export.
+#
+# Postponed, not realized yet modes:
+#
+# hide: Just hide export from new clients, leave existing connections as is.
+#       Remove export after all clients are disconnected. nbd-server-remove
+#       with mode=soft or mode=hard may be called after nbd-server-remove
+#       with mode=hide.
+#
+# soft: Hide export from new clients, answer with ESHUTDOWN for all further
+#       requests from existing clients. Remove export after all clients are
+#       disconnected. nbd-server-requests with mode=hard may be called after
+#       nbd-server-remove with mode=soft
+#
+# Since: 2.12
+##
+{'enum': 'NbdServerRemoveMode', 'data': ['safe', 'hard']}
+
+##
+# @nbd-server-remove:
+#
+# Remove NBD export by name.
+#
+# @name: Export name.
+#
+# @mode: Mode of command operation. See @NbdServerRemoveMode description.
+#        Default is 'safe'.
+#
+# Returns: error if
+#            - the server is not running
+#            - export is not found
+#            - mode is 'safe' and there are existing connections
+#
+# Since: 2.12
+##
+{ 'command': 'nbd-server-remove',
+  'data': {'name': 'str', '*mode': 'NbdServerRemoveMode'} }
+
+##
 # @nbd-server-stop:
 #
 # Stop QEMU's embedded NBD server, and unregister all devices previously
diff --git a/include/block/nbd.h b/include/block/nbd.h
index 978e443366..ee74ec391a 100644
--- a/include/block/nbd.h
+++ b/include/block/nbd.h
@@ -261,6 +261,7 @@ NBDExport *nbd_export_new(BlockDriverState *bs, off_t dev_offset, off_t size,
                           bool writethrough, BlockBackend *on_eject_blk,
                           Error **errp);
 void nbd_export_close(NBDExport *exp);
+void nbd_export_remove(NBDExport *exp, NbdServerRemoveMode mode, Error **errp);
 void nbd_export_get(NBDExport *exp);
 void nbd_export_put(NBDExport *exp);
 
diff --git a/blockdev-nbd.c b/blockdev-nbd.c
index 104789e521..a9f79c6778 100644
--- a/blockdev-nbd.c
+++ b/blockdev-nbd.c
@@ -189,6 +189,30 @@ void qmp_nbd_server_add(const char *device, bool has_name, const char *name,
     nbd_export_put(exp);
 }
 
+void qmp_nbd_server_remove(const char *name,
+                           bool has_mode, NbdServerRemoveMode mode,
+                           Error **errp)
+{
+    NBDExport *exp;
+
+    if (!nbd_server) {
+        error_setg(errp, "NBD server not running");
+        return;
+    }
+
+    exp = nbd_export_find(name);
+    if (exp == NULL) {
+        error_setg(errp, "Export '%s' is not found", name);
+        return;
+    }
+
+    if (!has_mode) {
+        mode = NBD_SERVER_REMOVE_MODE_SAFE;
+    }
+
+    nbd_export_remove(exp, mode, errp);
+}
+
 void qmp_nbd_server_stop(Error **errp)
 {
     nbd_export_close_all();
diff --git a/nbd/server.c b/nbd/server.c
index 6cf2eeb2c1..fdb6be7016 100644
--- a/nbd/server.c
+++ b/nbd/server.c
@@ -1177,6 +1177,27 @@ void nbd_export_close(NBDExport *exp)
     nbd_export_put(exp);
 }
 
+void nbd_export_remove(NBDExport *exp, NbdServerRemoveMode mode, Error **errp)
+{
+    NBDClient *client;
+    int nb_clients = 0;
+
+    if (mode == NBD_SERVER_REMOVE_MODE_HARD || QTAILQ_EMPTY(&exp->clients)) {
+        nbd_export_close(exp);
+        return;
+    }
+
+    assert(mode == NBD_SERVER_REMOVE_MODE_SAFE);
+
+    QTAILQ_FOREACH(client, &exp->clients, next) {
+        nb_clients++;
+    }
+
+    error_setg(errp, "NBD export '%s' has %d active connection%s. To force "
+               "remove it (and hard disconnect clients) use mode='hard'",
+               exp->name, nb_clients, nb_clients == 1 ? "" : "s");
+}
+
 void nbd_export_get(NBDExport *exp)
 {
     assert(exp->refcount > 0);
-- 
2.11.1

[Qemu-devel] [PATCH v2 4/6] iotest 147: add cases to test new @name parameter of nbd-server-add

[Vladimir Sementsov-Ogievskiy]

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
---
 tests/qemu-iotests/147     | 68 +++++++++++++++++++++++++++++++++++++---------
 tests/qemu-iotests/147.out |  4 +--
 2 files changed, 57 insertions(+), 15 deletions(-)

diff --git a/tests/qemu-iotests/147 b/tests/qemu-iotests/147
index 90f40ed245..d2081df84b 100755
--- a/tests/qemu-iotests/147
+++ b/tests/qemu-iotests/147
@@ -38,8 +38,8 @@ def flatten_sock_addr(crumpled_address):
 
 
 class NBDBlockdevAddBase(iotests.QMPTestCase):
-    def blockdev_add_options(self, address, export=None):
-        options = { 'node-name': 'nbd-blockdev',
+    def blockdev_add_options(self, address, export, node_name):
+        options = { 'node-name': node_name,
                     'driver': 'raw',
                     'file': {
                         'driver': 'nbd',
@@ -50,23 +50,28 @@ class NBDBlockdevAddBase(iotests.QMPTestCase):
             options['file']['export'] = export
         return options
 
-    def client_test(self, filename, address, export=None):
-        bao = self.blockdev_add_options(address, export)
+    def client_test(self, filename, address, export=None,
+                    node_name='nbd-blockdev', delete=True):
+        bao = self.blockdev_add_options(address, export, node_name)
         result = self.vm.qmp('blockdev-add', **bao)
         self.assert_qmp(result, 'return', {})
 
+        found = False
         result = self.vm.qmp('query-named-block-nodes')
         for node in result['return']:
-            if node['node-name'] == 'nbd-blockdev':
+            if node['node-name'] == node_name:
+                found = True
                 if isinstance(filename, str):
                     self.assert_qmp(node, 'image/filename', filename)
                 else:
                     self.assert_json_filename_equal(node['image']['filename'],
                                                     filename)
                 break
+        self.assertTrue(found)
 
-        result = self.vm.qmp('blockdev-del', node_name='nbd-blockdev')
-        self.assert_qmp(result, 'return', {})
+        if delete:
+            result = self.vm.qmp('blockdev-del', node_name=node_name)
+            self.assert_qmp(result, 'return', {})
 
 
 class QemuNBD(NBDBlockdevAddBase):
@@ -125,26 +130,63 @@ class BuiltinNBD(NBDBlockdevAddBase):
         except OSError:
             pass
 
-    def _server_up(self, address):
+    def _server_up(self, address, export_name=None, export_name2=None):
         result = self.server.qmp('nbd-server-start', addr=address)
         self.assert_qmp(result, 'return', {})
 
-        result = self.server.qmp('nbd-server-add', device='nbd-export')
+        if export_name is None:
+            result = self.server.qmp('nbd-server-add', device='nbd-export')
+        else:
+            result = self.server.qmp('nbd-server-add', device='nbd-export',
+                                     name=export_name)
         self.assert_qmp(result, 'return', {})
 
+        if export_name2 is not None:
+            result = self.server.qmp('nbd-server-add', device='nbd-export',
+                                     name=export_name2)
+            self.assert_qmp(result, 'return', {})
+
+
     def _server_down(self):
         result = self.server.qmp('nbd-server-stop')
         self.assert_qmp(result, 'return', {})
 
-    def test_inet(self):
+    def do_test_inet(self, export_name=None):
         address = { 'type': 'inet',
                     'data': {
                         'host': 'localhost',
                         'port': str(NBD_PORT)
                     } }
-        self._server_up(address)
-        self.client_test('nbd://localhost:%i/nbd-export' % NBD_PORT,
-                         flatten_sock_addr(address), 'nbd-export')
+        self._server_up(address, export_name)
+        export_name = export_name or 'nbd-export'
+        self.client_test('nbd://localhost:%i/%s' % (NBD_PORT, export_name),
+                         flatten_sock_addr(address), export_name)
+        self._server_down()
+
+    def test_inet_default_export_name(self):
+        self.do_test_inet()
+
+    def test_inet_same_export_name(self):
+        self.do_test_inet('nbd-export')
+
+    def test_inet_different_export_name(self):
+        self.do_test_inet('shadow')
+
+    def test_inet_two_exports(self):
+        address = { 'type': 'inet',
+                    'data': {
+                        'host': 'localhost',
+                        'port': str(NBD_PORT)
+                    } }
+        self._server_up(address, 'exp1', 'exp2')
+        self.client_test('nbd://localhost:%i/%s' % (NBD_PORT, 'exp1'),
+                         flatten_sock_addr(address), 'exp1', 'node1', False)
+        self.client_test('nbd://localhost:%i/%s' % (NBD_PORT, 'exp2'),
+                         flatten_sock_addr(address), 'exp2', 'node2', False)
+        result = self.vm.qmp('blockdev-del', node_name='node1')
+        self.assert_qmp(result, 'return', {})
+        result = self.vm.qmp('blockdev-del', node_name='node2')
+        self.assert_qmp(result, 'return', {})
         self._server_down()
 
     def test_inet6(self):
diff --git a/tests/qemu-iotests/147.out b/tests/qemu-iotests/147.out
index 3f8a935a08..dae404e278 100644
--- a/tests/qemu-iotests/147.out
+++ b/tests/qemu-iotests/147.out
@@ -1,5 +1,5 @@
-......
+.........
 ----------------------------------------------------------------------
-Ran 6 tests
+Ran 9 tests
 
 OK
-- 
2.11.1

[Qemu-devel] [PATCH v2 5/6] iotests: implement QemuIoInteractive class

[Vladimir Sementsov-Ogievskiy]

Implement QemuIoInteractive to test nbd-server-remove command when
there are active connections.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
 tests/qemu-iotests/iotests.py | 38 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 38 insertions(+)

diff --git a/tests/qemu-iotests/iotests.py b/tests/qemu-iotests/iotests.py
index 44477e9295..5a10b2d534 100644
--- a/tests/qemu-iotests/iotests.py
+++ b/tests/qemu-iotests/iotests.py
@@ -93,6 +93,44 @@ def qemu_io(*args):
         sys.stderr.write('qemu-io received signal %i: %s\n' % (-exitcode, ' '.join(args)))
     return subp.communicate()[0]
 
+
+class QemuIoInteractive:
+    def __init__(self, *args):
+        self.args = qemu_io_args + list(args)
+        self._p = subprocess.Popen(self.args, stdin=subprocess.PIPE,
+                                   stdout=subprocess.PIPE,
+                                   stderr=subprocess.STDOUT)
+        assert self._p.stdout.read(9) == 'qemu-io> '
+
+    def close(self):
+        self._p.communicate('q\n')
+
+    def _read_output(self):
+        pattern = 'qemu-io> '
+        n = len(pattern)
+        pos = 0
+        s = []
+        while pos != n:
+            c = self._p.stdout.read(1)
+            # check unexpected EOF
+            assert c != ''
+            s.append(c)
+            if c == pattern[pos]:
+                pos += 1
+            else:
+                pos = 0
+
+        return ''.join(s[:-n])
+
+    def cmd(self, cmd):
+        # quit command is in close(), '\n' is added automatically
+        assert '\n' not in cmd
+        cmd = cmd.strip()
+        assert cmd != 'q' and cmd != 'quit'
+        self._p.stdin.write(cmd + '\n')
+        return self._read_output()
+
+
 def qemu_nbd(*args):
     '''Run qemu-nbd in daemon mode and return the parent's exit code'''
     return subprocess.call(qemu_nbd_args + ['--fork'] + list(args))
-- 
2.11.1

[Qemu-devel] [PATCH v2 6/6] iotest 201: new test for qmp nbd-server-remove

[Vladimir Sementsov-Ogievskiy]

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
 tests/qemu-iotests/201     | 159 +++++++++++++++++++++++++++++++++++++++++++++
 tests/qemu-iotests/201.out |   5 ++
 tests/qemu-iotests/group   |   1 +
 3 files changed, 165 insertions(+)
 create mode 100644 tests/qemu-iotests/201
 create mode 100644 tests/qemu-iotests/201.out

diff --git a/tests/qemu-iotests/201 b/tests/qemu-iotests/201
new file mode 100644
index 0000000000..1ac6d953c0
--- /dev/null
+++ b/tests/qemu-iotests/201
@@ -0,0 +1,159 @@
+#!/usr/bin/env python
+#
+# Tests for qmp command nbd-server-remove.
+#
+# Copyright (c) 2017 Virtuozzo International GmbH
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+
+import os
+import sys
+import iotests
+import time
+from iotests import qemu_img, qemu_io, filter_qemu_io, QemuIoInteractive
+
+nbd_port = '10900'
+nbd_uri = 'nbd+tcp://localhost:' + nbd_port + '/exp'
+disk = os.path.join(iotests.test_dir, 'disk')
+
+
+class TestNbdServerRemove(iotests.QMPTestCase):
+    def setUp(self):
+        qemu_img('create', '-f', iotests.imgfmt, disk, '1M')
+
+        self.vm = iotests.VM().add_drive(disk)
+        self.vm.launch()
+
+        address = {
+            'type': 'inet',
+            'data': {
+                'host': 'localhost',
+                'port': nbd_port
+            }
+        }
+
+        result = self.vm.qmp('nbd-server-start', addr=address)
+        self.assert_qmp(result, 'return', {})
+        result = self.vm.qmp('nbd-server-add', device='drive0', name='exp')
+        self.assert_qmp(result, 'return', {})
+
+    def tearDown(self):
+        self.vm.shutdown()
+        os.remove(disk)
+
+    def remove_export(self, name, mode=None):
+        if mode is None:
+            return self.vm.qmp('nbd-server-remove', name=name)
+        else:
+            return self.vm.qmp('nbd-server-remove', name=name, mode=mode)
+
+    def assertExportNotFound(self, name):
+        result = self.vm.qmp('nbd-server-remove', name=name)
+        self.assert_qmp(result, 'error/desc', "Export 'exp' is not found")
+
+    def assertExistingClients(self, result):
+        self.assert_qmp(result, 'error/desc',
+                        "NBD export 'exp' has 1 active connection. To force "
+                        "remove it (and hard disconnect clients) use "
+                        "mode='hard'")
+
+    def assertReadOk(self, qemu_io_output):
+        self.assertEqual(
+                filter_qemu_io(qemu_io_output).strip(),
+                'read 512/512 bytes at offset 0\n' +
+                '512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)')
+
+    def assertReadFailed(self, qemu_io_output):
+        self.assertEqual(filter_qemu_io(qemu_io_output).strip(),
+                         'read failed: Input/output error')
+
+    def assertConnectFailed(self, qemu_io_output):
+        self.assertEqual(filter_qemu_io(qemu_io_output).strip(),
+                         "can't open device nbd+tcp://localhost:" + nbd_port +
+                         "/exp: Requested export not available\n"
+                         "server reported: export 'exp' not present")
+
+    def do_test_connect_after_remove(self, mode=None):
+        args = ('-r', '-f', 'raw', '-c', 'read 0 512', nbd_uri)
+        self.assertReadOk(qemu_io(*args))
+
+        result = self.remove_export('exp', mode)
+        self.assert_qmp(result, 'return', {})
+
+        self.assertExportNotFound('exp')
+        self.assertConnectFailed(qemu_io(*args))
+
+    def test_connect_after_remove_default(self):
+        self.do_test_connect_after_remove()
+
+    def test_connect_after_remove_safe(self):
+        self.do_test_connect_after_remove('safe')
+
+    def test_connect_after_remove_force(self):
+        self.do_test_connect_after_remove('hard')
+
+    def do_test_remove_during_connect_safe(self, mode=None):
+        qio = QemuIoInteractive('-r', '-f', 'raw', nbd_uri)
+        self.assertReadOk(qio.cmd('read 0 512'))
+
+        result = self.remove_export('exp', mode)
+        self.assertExistingClients(result)
+
+        self.assertReadOk(qio.cmd('read 0 512'))
+
+        qio.close()
+
+        result = self.remove_export('exp', mode)
+        self.assert_qmp(result, 'return', {})
+
+        self.assertExportNotFound('exp')
+
+    def test_remove_during_connect_default(self):
+        self.do_test_remove_during_connect_safe()
+
+    def test_remove_during_connect_safe(self):
+        self.do_test_remove_during_connect_safe('safe')
+
+    def test_remove_during_connect_hard(self):
+        qio = QemuIoInteractive('-r', '-f', 'raw', nbd_uri)
+        self.assertReadOk(qio.cmd('read 0 512'))
+
+        result = self.remove_export('exp', 'hard')
+        self.assert_qmp(result, 'return', {})
+
+        self.assertReadFailed(qio.cmd('read 0 512'))
+        self.assertExportNotFound('exp')
+
+        qio.close()
+
+    def test_remove_during_connect_safe_hard(self):
+        qio = QemuIoInteractive('-r', '-f', 'raw', nbd_uri)
+        self.assertReadOk(qio.cmd('read 0 512'))
+
+        result = self.remove_export('exp', 'safe')
+        self.assertExistingClients(result)
+
+        self.assertReadOk(qio.cmd('read 0 512'))
+
+        result = self.remove_export('exp', 'hard')
+        self.assert_qmp(result, 'return', {})
+
+        self.assertExportNotFound('exp')
+        self.assertReadFailed(qio.cmd('read 0 512'))
+        qio.close()
+
+
+if __name__ == '__main__':
+    iotests.main()
diff --git a/tests/qemu-iotests/201.out b/tests/qemu-iotests/201.out
new file mode 100644
index 0000000000..2f7d3902f2
--- /dev/null
+++ b/tests/qemu-iotests/201.out
@@ -0,0 +1,5 @@
+.......
+----------------------------------------------------------------------
+Ran 7 tests
+
+OK
diff --git a/tests/qemu-iotests/group b/tests/qemu-iotests/group
index 93d96fb22f..f07d3e3df6 100644
--- a/tests/qemu-iotests/group
+++ b/tests/qemu-iotests/group
@@ -197,5 +197,6 @@
 197 rw auto quick
 198 rw auto
 200 rw auto
+201 rw auto quick
 202 rw auto quick
 203 rw auto
-- 
2.11.1

Re: [Qemu-devel] [PATCH v2 2/6] hmp: add name parameter to nbd_server_add

[Eric Blake]

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On 01/18/2018 12:11 PM, Vladimir Sementsov-Ogievskiy wrote:
> Support name parameter for HMP too.
> 
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> ---
>  hmp.c           | 3 ++-
>  hmp-commands.hx | 9 +++++----
>  2 files changed, 7 insertions(+), 5 deletions(-)
> 

> +++ b/hmp-commands.hx
> @@ -1553,8 +1553,8 @@ ETEXI
>  
>      {
>          .name       = "nbd_server_add",
> -        .args_type  = "writable:-w,device:B",
> -        .params     = "nbd_server_add [-w] device",
> +        .args_type  = "name:-n,writable:-w,device:B",
> +        .params     = "nbd_server_add [-n] [-w] device",

Doesn't quite look like my proposal:
https://lists.gnu.org/archive/html/qemu-devel/2018-01/msg01639.html

-        .args_type  = "writable:-w,device:B",
-        .params     = "nbd_server_add [-w] device",
+        .args_type  = "writable:-w,device:B,name:s?",
+        .params     = "nbd_server_add [-w] device [name]",

In fact, using -n is not quite right, because that's just a boolean flag
rather than a string.

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org


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Re: [Qemu-devel] [PATCH v2 3/6] qapi: add nbd-server-remove

[Eric Blake]

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On 01/18/2018 12:11 PM, Vladimir Sementsov-Ogievskiy wrote:
> Add command for export removing. It is needed for cases when we

s/export removing/removing an export/

> don't want to keep export after the operation on it was completed.
> The other example is temporary node, created with blockdev-add.
> If we want to delete it we should firstly remove corresponding
> NBD export.
> 

No HMP counterpart? I can give a quick shot at that, as a followup patch.

> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> ---
>  qapi/block.json     | 45 +++++++++++++++++++++++++++++++++++++++++++++
>  include/block/nbd.h |  1 +
>  blockdev-nbd.c      | 24 ++++++++++++++++++++++++
>  nbd/server.c        | 21 +++++++++++++++++++++
>  4 files changed, 91 insertions(+)
> 
> diff --git a/qapi/block.json b/qapi/block.json
> index 353e3a45bd..ddf73932ce 100644
> --- a/qapi/block.json
> +++ b/qapi/block.json
> @@ -228,6 +228,51 @@
>    'data': {'device': 'str', '*name': 'str', '*writable': 'bool'} }
>  
>  ##
> +# @NbdServerRemoveMode:
> +#
> +# Mode of NBD export removing.

Mode for removing an NBD export.

> +#
> +# @safe: Remove export if there are no existing connections, fail otherwise.
> +#
> +# @hard: Drop all connections immediately and remove export.
> +#
> +# Postponed, not realized yet modes:

Maybe:

Potential additional modes to be added in the future:

> +#
> +# hide: Just hide export from new clients, leave existing connections as is.
> +#       Remove export after all clients are disconnected. nbd-server-remove
> +#       with mode=soft or mode=hard may be called after nbd-server-remove
> +#       with mode=hide.

mode=safe could also be called; I don't see that this last sentence adds
much.

> +#
> +# soft: Hide export from new clients, answer with ESHUTDOWN for all further
> +#       requests from existing clients. Remove export after all clients are
> +#       disconnected. nbd-server-requests with mode=hard may be called after
> +#       nbd-server-remove with mode=soft

Again, the last sentence doesn't add mouch (I guess you're arguing that
requesting a hide doesn't make much sense after a soft disconnect has
already started; but I don't see any harm in permitting it as a no-op).

> +#
> +# Since: 2.12
> +##
> +{'enum': 'NbdServerRemoveMode', 'data': ['safe', 'hard']}
> +
> +##
> +# @nbd-server-remove:
> +#
> +# Remove NBD export by name.
> +#
> +# @name: Export name.
> +#
> +# @mode: Mode of command operation. See @NbdServerRemoveMode description.
> +#        Default is 'safe'.
> +#
> +# Returns: error if
> +#            - the server is not running
> +#            - export is not found
> +#            - mode is 'safe' and there are existing connections
> +#
> +# Since: 2.12
> +##
> +{ 'command': 'nbd-server-remove',
> +  'data': {'name': 'str', '*mode': 'NbdServerRemoveMode'} }

Looks reasonable.


> +++ b/nbd/server.c
> @@ -1177,6 +1177,27 @@ void nbd_export_close(NBDExport *exp)
>      nbd_export_put(exp);
>  }
>  
> +void nbd_export_remove(NBDExport *exp, NbdServerRemoveMode mode, Error **errp)
> +{
> +    NBDClient *client;
> +    int nb_clients = 0;
> +
> +    if (mode == NBD_SERVER_REMOVE_MODE_HARD || QTAILQ_EMPTY(&exp->clients)) {
> +        nbd_export_close(exp);
> +        return;
> +    }
> +
> +    assert(mode == NBD_SERVER_REMOVE_MODE_SAFE);
> +
> +    QTAILQ_FOREACH(client, &exp->clients, next) {
> +        nb_clients++;
> +    }
> +
> +    error_setg(errp, "NBD export '%s' has %d active connection%s. To force "
> +               "remove it (and hard disconnect clients) use mode='hard'",
> +               exp->name, nb_clients, nb_clients == 1 ? "" : "s");

Playing games with English pluralization doesn't work too well in error
messages, if we ever want to allow translations; does the number of
active clients actually matter?  Also, error_setg() recommends against
using '.' or more than one sentence.  Better might be:

error_setg(errp, "export '%s' still in use");
error_append_hint(errp, "Use mode='hard' to force client disconnect\n");

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org


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Re: [Qemu-devel] [PATCH v2 6/6] iotest 201: new test for qmp nbd-server-remove

[Eric Blake]

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On 01/18/2018 12:11 PM, Vladimir Sementsov-Ogievskiy wrote:
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> ---
>  tests/qemu-iotests/201     | 159 +++++++++++++++++++++++++++++++++++++++++++++
>  tests/qemu-iotests/201.out |   5 ++
>  tests/qemu-iotests/group   |   1 +
>  3 files changed, 165 insertions(+)
>  create mode 100644 tests/qemu-iotests/201
>  create mode 100644 tests/qemu-iotests/201.out
> 

> +
> +    def assertExistingClients(self, result):
> +        self.assert_qmp(result, 'error/desc',
> +                        "NBD export 'exp' has 1 active connection. To force "
> +                        "remove it (and hard disconnect clients) use "
> +                        "mode='hard'")

Needs tweaking if we massage the error message earlier in the series.

I'm still worried that this test may fail spuriously due to a hard-coded
port, but some testing is better than none, and if the CI engines don't
immediately reject it, whoever first encounters it will be nice and let
us know.

Reviewed-by: Eric Blake <eblake@redhat.com>

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org


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Re: [Qemu-devel] [PATCH v2 0/6] nbd export qmp interface

[Eric Blake]

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On 01/18/2018 12:11 PM, Vladimir Sementsov-Ogievskiy wrote:
> v2:
> 01: tweak comment
>     add Eric's r-b
> 02: new patch
> 03: rewritten, to move form 'bool force' flag to 'enum mode' parameter
> 04: add Eric's r-b
> 05: improve commit message
>     tweak comment
> 06: rebase on 03 changes
>     make PEP8 happy
>     some other tweaks
>     I've left nbd_port variable hard-set to 10900. I think all such things
>     should be fixed together, and it is simple to change in future
>     nbd_port = '10900'
>     to
>     nbd_port = iotests.get_free_port()
>     if needed.
> 
> [Unfortunately, qmp query-nbd-server is not finished yet, coming soon,
>  but may be after my vocation on the next week]

Enjoy your time off. I think the series is nearly ready to go; I had
some tweaks that I suggested, and will probably replace your 2/6 with my
counterproposal, but I don't mind doing that cleanup if you don't have
time to respin.  I'll give it a few more days in case anyone else has
comments, then add it to my NBD queue.

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org


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Re: [Qemu-devel] [PATCH v2 2/6] hmp: add name parameter to nbd_server_add

[Vladimir Sementsov-Ogievskiy]

19.01.2018 00:08, Eric Blake wrote:
> On 01/18/2018 12:11 PM, Vladimir Sementsov-Ogievskiy wrote:
>> Support name parameter for HMP too.
>>
>> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
>> ---
>>   hmp.c           | 3 ++-
>>   hmp-commands.hx | 9 +++++----
>>   2 files changed, 7 insertions(+), 5 deletions(-)
>>
>> +++ b/hmp-commands.hx
>> @@ -1553,8 +1553,8 @@ ETEXI
>>   
>>       {
>>           .name       = "nbd_server_add",
>> -        .args_type  = "writable:-w,device:B",
>> -        .params     = "nbd_server_add [-w] device",
>> +        .args_type  = "name:-n,writable:-w,device:B",
>> +        .params     = "nbd_server_add [-n] [-w] device",
> Doesn't quite look like my proposal:
> https://lists.gnu.org/archive/html/qemu-devel/2018-01/msg01639.html
>
> -        .args_type  = "writable:-w,device:B",
> -        .params     = "nbd_server_add [-w] device",
> +        .args_type  = "writable:-w,device:B,name:s?",
> +        .params     = "nbd_server_add [-w] device [name]",
>
> In fact, using -n is not quite right, because that's just a boolean flag
> rather than a string.
>

Strange, I don't have your letter. Let's use yours, of course.

-- 
Best regards,
Vladimir

Re: [Qemu-devel] [PATCH v2 6/6] iotest 201: new test for qmp nbd-server-remove

[Vladimir Sementsov-Ogievskiy]

19.01.2018 01:43, Eric Blake wrote:
> On 01/18/2018 12:11 PM, Vladimir Sementsov-Ogievskiy wrote:
>> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
>> ---
>>   tests/qemu-iotests/201     | 159 +++++++++++++++++++++++++++++++++++++++++++++
>>   tests/qemu-iotests/201.out |   5 ++
>>   tests/qemu-iotests/group   |   1 +
>>   3 files changed, 165 insertions(+)
>>   create mode 100644 tests/qemu-iotests/201
>>   create mode 100644 tests/qemu-iotests/201.out
>>
>> +
>> +    def assertExistingClients(self, result):
>> +        self.assert_qmp(result, 'error/desc',
>> +                        "NBD export 'exp' has 1 active connection. To force "
>> +                        "remove it (and hard disconnect clients) use "
>> +                        "mode='hard'")
> Needs tweaking if we massage the error message earlier in the series.
>
> I'm still worried that this test may fail spuriously due to a hard-coded
> port, but some testing is better than none, and if the CI engines don't
> immediately reject it, whoever first encounters it will be nice and let
> us know.
>
> Reviewed-by: Eric Blake <eblake@redhat.com>
>

Looked through other tests, looks like same approach is only in 147, and 
other iotests uses unix sockets for nbd-server-start. May be, it is 
better to move to unix socket here.
I'll resend today with unix-socket.

-- 
Best regards,
Vladimir

Re: [Qemu-devel] [PATCH v2 0/6] nbd export qmp interface

[Kevin Wolf]

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Am 18.01.2018 um 23:45 hat Eric Blake geschrieben:
> On 01/18/2018 12:11 PM, Vladimir Sementsov-Ogievskiy wrote:
> > v2:
> > 01: tweak comment
> >     add Eric's r-b
> > 02: new patch
> > 03: rewritten, to move form 'bool force' flag to 'enum mode' parameter
> > 04: add Eric's r-b
> > 05: improve commit message
> >     tweak comment
> > 06: rebase on 03 changes
> >     make PEP8 happy
> >     some other tweaks
> >     I've left nbd_port variable hard-set to 10900. I think all such things
> >     should be fixed together, and it is simple to change in future
> >     nbd_port = '10900'
> >     to
> >     nbd_port = iotests.get_free_port()
> >     if needed.
> > 
> > [Unfortunately, qmp query-nbd-server is not finished yet, coming soon,
> >  but may be after my vocation on the next week]
> 
> Enjoy your time off. I think the series is nearly ready to go; I had
> some tweaks that I suggested, and will probably replace your 2/6 with my
> counterproposal, but I don't mind doing that cleanup if you don't have
> time to respin.  I'll give it a few more days in case anyone else has
> comments, then add it to my NBD queue.

I haven't reviewed the patches in detail, but the API changes look good
to me.

Kevin

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